1. Field of the Invention
The invention relates to a feed accessory apparatus for feeding the tail of a material web into a roll machine.
2. Discussion of Background Information
The material web is subjected to increased pressure and, if applicable, also to elevated temperature in the nips. The effects intended to be achieved hereby extend from compression of the material web to improvement of the surface qualities. To this end, it is often necessary for the material web to run through several nips in sequence. The rolls here are generally arranged in what is known as a roll stack, i.e., their axes lie in a common plane.
Before treatment of the material web can be allowed to start, the material web must be threaded into the roll machine, i.e., it must be lead through the first nip, passed it around a guide roll, lead through the next nip, etc. In the case of a paper web, this is often handled in such a way that the tail of the paper web is folded into a point which then has a certain stiffness so it can be passed through the individual nips or roll gaps. Alternatively, a narrow strip can be cut out at the end of the paper web and then guided through the calender. Once the strip has run through the calender, the paper web can be widened again.
Feeding of the paper web can be done automatically, for instance, by guide devices which are known, e.g., from EP 0 232 689 A. The disadvantage of this design, however, is that the resources required and hence the costs for the installation are very high. Moreover, accessibility of the calender during operation is drastically reduced. If tears in the paper web occur, hazardous paper jams occur and sometimes damage is caused to equipment and rolls. It is difficult to see the moving paper web. The assembly costs at roll change are high. It is very costly to swing out the complete web guide system after feeding of the web and, in most cases, this cannot be done for space reasons.
Consequently, in many situations, the paper web is still threaded in by hand even today. During the process, the calender is set to operate slowly, and the paper web is then passed from nip to nip. This is a very labor-intensive procedure, and thus time consuming. What is extremely important is that a relatively high risk of injury exists in this context. The individual operator must reach relatively far into the calender to be able to slip the paper web into the nip. Even when the rolls are running slowly, there is still the risk that the operator's hand will be pulled along into the open nip. Contusions and other injuries frequently occur in this context.